Though I do imagine that it is related to "can't attack unless" abilities.

Some Brawl "hell queue" fun...Opponent had mana for one counterspell. I play a few mana dorks, then tap Nykthos for eight {G}. Six of this was spent to cast my commander (with commander tax), and unsurprisingly, it gets countered. Little did my opponent know I had a Craterhoof Behemoth in hand and still had enough mana to cast it...

Magic is a game of information. What you know and don't know is often decisive.

> I tap Nykthos for eight {G} and spend six to cast Fynn.

> In response, Disruption Protocol.

> (counts untapped lands and mana dorks, tapping as needed) With two {G} mana left in mana pool... I cast Craterhoof Behemoth.

I attack with all, and my opponent doesn't bother with declaring blockers.

Decklist: scryfall.com/@draconicpenguin/decks/…

Mana dorks that cost only {G} are effectively free when you have Nykthos because of the devotion mechanic, and they serve to buff Craterhoof.

Next up... I hope to return to Standard, and I'm planning to build a rotation-ready mono-red burn deck. I haven't had much experience with red lately, so this will be fun.